Electric discharge device circuit



1944. c. ABBOTT 2,354,654

I ELECTRIC DISCHARGE DEVICE CIRCUIT Filed Feb. 6, 1942 2 Sheets-Sheet 1 nnnu J ICAP. l I I VLine M. MatthewaAbbott, MENTOR Fi 2 BY ATTOIIQNEY 1944- I M. c. ABBOTT 2,354,654

. ELECTRIC DISCHARGE DEVICE CIRCUIT Filed Feb. .6. 1942 2 Sheets-Sheet 2 r 5 4? Fig: 3 A

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ATTORNEY Patented Aug. 1, 1944 Q ELECTRIC DISCHARGE DEVICE. CIRCUIT Matthew 9. Abbott, Ipswich, Mass., assig'nor to Sylvania Electric Products Inc., a corporation of Massachusetts Application February 6, 1942 Serial No. 429,793

4 Glaims. (Cl. 315-138) This invention relates to electric gaseous discharge lamps and in particular to apparatus for operating such lamps.

In the operation of fluorescent lamps, it is desirable that. the stroboscopic efiect be reduced to a minimum. The correction of this factor in three lamp circuits has been accomplished with improved results over that attained in two lamp circuits. However, this has been at'th cost of considerable wattage loss due to resistance ballast of the third lamp.

Therefore an object of my invention is to economically obtain operation of three lamps from a single phase circuit in a manner such that the light pulses, or stroboscopic effect, occur in turn at three equal intervals during each half cycle of the alternating current power source.

Another object of my invention is to provide adequate and economical starting circuits for said lamp operation.

A further object is the elimination of certain cathodes and the combining of three lamps so that three arcs may be sustained, each cut of phase with the other, in the same atmosphere.

Still another object is the reducing of said combination to a compact area with substantial- 1y long are paths but maintaining an equilibrium among said paths.

Other objects, advantages, and features will become apparent from the following specifications and accompanying drawings in which:

Figure 1 is a schematic diagram of the circuit of my invention;

'22, 5 and leading arc discharge circuit 4, I, choke coil 8, condenser III, I2, I, 2|, 20, 2, 22, 5 are established. The lagg ng circuit must be operated at a power factor of .5, i. e., 60 degrees, and the leading circuit must be operated at the same power factor so that the phase displacement of the two currents, one through are 3 and one through arc I, be 120 degrees. The current through are 2 is the sum of the currents through arc I and are 3.

As indicated in the vector diagram of Figure 2, the circuit currents must lead and lag by 60 each so that the magnitude of their vector sum is equal to either of the magnitudes of the two components. The currents flowing toward the joinder of the lamps will thus be 120 degrees apart electrically. The reactance of the condenser and choke in series with it, plus the reactance of the leading lamp itself, must be equal to the total reactance of the lagging circuit, within commercial tolerance; For best results the ratio of the condenser reactance to that of its series choke should 'be between 2.0 and 3.0 because values much less than this-minimum result in high condenser voltages. and have a deleterious effect on the uniformity of manufacture of the circuits because of the commercial condenser tolerances.

' Higher'values will result in abnormal distortion Figure 2 is a vector diagram of the lamp light or currents as connected according to my invention demonstrating their phase relationship;

Figure 3 is a schematic diagram of a' circuit which is a variation of that shown in Figure 1;

Figure 4 is another variation of said circuit as applied to an incorporated lamp;

Figure 5 is a schematic diagram of an application of the circuit shown in Figure 4:

In Figure l' the circuit is connected to any suitable source of alternating current by the leadin wires 4 and 5 either through the auto-transformer 6 or directly thereto. 1

. ings are connected as in the diagram: winding The circuit from leads 4 and 5 is completed through line I, choke coil 9, cathode I8, switch I1, starting transformer primary l5 and cathode 22. Induced currents in the secondaries I3 and I4 oi the starting transformer I6 heat cathodes l2, I9, 20 and 2| tothe same temperature as cathodes l8 and 22-. peated openings of this circuit at switch II, lagsins are discharge circuit 4, I, 9, l8, 3, I9, 20, 2, 5

On initial opening orre-.

of the current of this circuit. The reactance ratio increases with decrease of condenser reactance because the total reactance of the circuit is capacitive and constant so that the lamp current will beconstant.

Figure 3 is a variation of the circuit in Figure 1. It shows how a current-operated switch may take the place of the voltage-operated switch. It also shows other means of facilitating starting by addinganother delay switch 21 in series with electrode I2 and coil I3, and the additional windings 23, 2-4 and 25 on the core. These wind- 23 through aa to cathode I8; winding 24 through cc to cathode I2; and winding 25 to the cathode 22. Electrodes I9, 20 and 2i are connected to the winding I4 through bb in the same manner as in Figure 1. The circuits of arcs I and 2 and of 2 and 3 are connected parallel so that either pair will continue to burn as one are if the arc does not strike across the third at the first start. Also by addition of the second delay starting switch the unlitarc is given another opportunity to strike. v

Difl'erent switches may be used in starting these three lamp circuits such as using a current-operated thermal or magnetic element in series with vforr'n the resultant are 2 thus retaining the three phase lamp operation. The mercury Vapor will generally be at low pressure, say 6 microns, when the lamp is operated.

As in Figures 3 and 4, if the line current is of 15 arrangement of said second inductive impedance satisfactory voltage, say 110 v., the leads 4 and 5 may be tapped direct to the line, thus eliminating the auto-transformer 6.

' Another practical application of the advantages of the incorporated lamp may be visual zed in Figure 5 in which the three lamps are contained in a single disc shaped envelope, in which, 12. 22 and 18 are the filamentary electrodes placed in the centermost of several concentric channels which are divided by the'partitions 28, 29, and 30 to form equal lengthpaths for each arc, I being the leading are, 2 the resultant arc, and 3 the lagging arc. By this means the longest posslble arc paths are contained in a compact form. Because point P must be equi-distant along the .arc paths from all the filamentary electrodes,

the angles 01, 02, and 03 between the parti ions become very critical. They, must be substantially 60, 120 and 180. for uniformity in length of the arc paths.

What I claim is:

l. A circuit for the operation of three-arc discharges of equal magnitude in'electrical gaseous discharge devices havingat least three electrodes and in which there is present a leading current are discharge component, a lagging current are discharge component, and an arc discharge current in resultant phase with respect to said leading and'lagging currents; said circuit including: an inductive impedance ballast for the lagging current are discharge component; a capacitive impedance ballast for the leading current are discharge component; and' an arrangement for producing said resultant phase .arc discharge; said arrangement comprising a combination of said inductive and capacity impedances such as to displace the arc discharge current components from each other so that the magnitude of their vector sum is equal to either or the magnitudes of the two components, whereby said resultant phase are discharge is controlled jointly by the current of said leading and lagging arc discharge com-.

ponents.

2.-A circuit for the operation of three-arcdischarges of equal magnitude in electric gaseous discharge devices having at least three electrodes and in which there is present a leading current are discharge, a lagging current are discharge,

5 and an arc discharge current in resultant phase with respect to said leading and lagging currents, said circuit including: an inductive impedance electrically connected between one of said electrodes and one side of the line voltage; a second inductive impedance and a capacitive impedance in series, electrically -connected between a second of said electrodes and said side of the line voltage; and a combination, comprising said first inductive impedance in parallel with said series and said capacitive impedance, electrically connected between a third of said electrodes and said side of the line voltage.

3. A circuit for the operation of three-arc dis- 20 charges of equal magnitude in electric gaseous discharge devices having at least three electrodes andin which there is present a leading current arc discharge, a lagging current are discharge, and an arc discharge current in resultant phase 5 with respect to said' leading and lagging currents,

said circuit including: an inductive impedance electrically connected between one of said electrodes and one side of the line voltage; a second inductive impedance and a capacitive impedance in series, electrically connected between a second of said electrodes and said side of the line voltage; and a combination, comprising said first inductive impedance in parallel with said series arrangement of said second inductive impedance ss 'and said capacitive impedance, electrically connected between a third of said electrodes and said side of the line voltage; with the ratio of the reactances of said capacitive impedance and said second inductive impedance in series therewith 40 being between 2.5 and 3.0.

4. An electric gaseous discharge lamp for three are discharge operation, said lamp comprising:

'an envelope having a plurality of partitions in I 'maze-like arrangement; three electrodes mounted centrally of said maze-like arrangements cencurrents is vectorially equal to and opposite the other.

MATTHEW C. ABBOTT. 

